1. Field of the Invention
The present invention relates to a semiconductor device testing apparatus, and more particularly to a semiconductor device testing apparatus using a contact sheet made of a flexible and thin sheet material and a high frequency probe having a general structure, in which the supply voltage is applied to the semiconductor device from the power source via an external terminal located on the contact sheet, and in which the high frequency probe contacts with a signal electrode and performs the measurement.
2. Description of the Related Art
A semiconductor device that operates in a bandwidth of equal to or more than 10 GHz often has more supply voltage and ground electrodes, that is, more electrodes for high and low supply voltages and less signal electrodes for inputting and/or outputting operating signals in order to lower the power source impedance. A flexible membrane sheet is often used in a testing apparatus to measure the electrical characteristics of such a semiconductor device.
FIG. 1 is a cross sectional view of a probe card described in Kokusai Kokai No. WO98/58266 as a probe card structure of a semiconductor device testing apparatus using a conventional flexible membrane sheet.
In this figure, by contacting a pad 23a of a semiconductor device 23 to a bump 5c on a flexible membrane sheet 5 located on a printed board 4, power source voltage is supplied through a power supply wiring and a signal is extracted from a signal wiring by connecting a terminal 6 to the wiring on the printed board 4. Particularly, when conducting a high frequency signal, a micro-strip structure, in which signal wiring is formed on the front surface and a ground line is entirely formed on the back surface, is often used.
However, as seen in this figure, because the membrane sheet 5 is inserted in bent shape, the distance between a signal line on the front surface and a ground line on the back surface changes at the bent area and the characteristic impedance of the micro-strip line, which is determined by the distance between the signal line and the ground line, changes. Moreover, the characteristic impedance is disturbed by a discontinuous structure at a junction between the membrane sheet 5 and the printed board 4. When testing a semiconductor device whose operating frequency is low, these effects are small and it is possible to perform the measurement. However, when testing a semiconductor device whose operating frequency is equal to or more than 10 GHz, these effects are large and there is a problem that using a probe structure with the conventional membrane sheet 5 limits the frequency characteristic of a line which transfers a high frequency signal, and the electrical characteristic of the semiconductor device cannot be measured accurately.
An object of the present invention, related to the than the contact sheet, covering the first and second supply voltage applying electrodes and located on the opposite side from the side where said first and second supply voltage applying electrodes of the contact sheet are located; a base plate having a concavity with a shape that matches the outer dimension and thickness of the elastic sheet and the contact sheet, and installed the elastic sheet and the contact sheet in the concavity such that the first and second supply voltage applying electrodes are exposed; a power source portion for applying a predetermined supply voltage to the external terminal on said contact sheet; and a probe portion having a position setting section moving X and Y directions, and Z direction perpendicular to the X and Y directions, assuming the surface of the base plate to be an X-Y plane, and a high frequency probe coupled to the position setting section to electrically contact to the signal electrode of the semiconductor device.
The above mentioned semiconductor device testing apparatus may be such a structure as the contact sheet has a first opening formed at a portion where the first and second wirings are absent; the elastic sheet has a second opening connected with the first opening; the base plate has a third opening connected with the second opening; and a high frequency probe is contacted to the signal electrode through the third, second and first openings.
Further, the semiconductor device testing apparatus may be a structure in which a through-hole filled with a conductive material is formed at a portion of the contact sheet on the measurement of an electrical characteristic of a semiconductor device that has many electrodes and operates at high frequency, is to provide a semiconductor device testing apparatus that applies supply voltages including ground voltage by making an accurate contact with many electrodes, and performs a high frequency signal measurement.
In order to achieve the above object, according to the present invention, there is provided a semiconductor device testing apparatus for testing an electrical characteristic of a semiconductor device which has a first electrode applied a high supply voltage, e.g. positive voltage from a power source, a second electrode applied a low power source voltage, e.g. ground voltage or negative voltage from a power source and signal electrode for inputting and/or outputting an operating signal formed, respectively, on its front surface side. The apparatus comprises a device stage holding the semiconductor device to be tested; a contact sheet including a insulating sheet, first and second supply voltage applying electrodes on the insulating sheet and electrically contacting with the first and second electrodes of the semiconductor device, respectively, at the testing state, first and second external terminals located on a peripheral portion on the insulating sheet and positioned with a lager interval each other than that of the first and second supply voltage applying electrodes, a first wiring connecting the first supply voltage applying electrode and the first external terminal, a second wiring connecting the second supply voltage applying electrode and the second external terminal; elastic sheet having a smaller size signal electrode; a first signal testing electrode connected to the conductive material at one end of the through-hole and contacting the signal electrode is formed; a extracting out wiring layer connected to the conductive material at the other of the through-hole and extending on the contact sheet is formed; a second signal testing electrode connected to the extracting out wiring layer is formed; the high frequency probe is contacted to the second signal testing electrode of the semiconductor device through openings provided, respectively, in the base plate and the elastic sheet; and a support ring located on the side opposite from the second signal testing electrode is provided to support the portion of the contact sheet where the second signal testing electrode is formed.
Moreover, the semiconductor device testing apparatus may be a structure in which a through-hole filled with a conductive material is formed at a portion of the contact sheet on the signal electrode; a first signal testing electrode connected to the conductive material at one end of the through-hole and contacting the signal electrode is formed; a second signal testing electrode connected to the conductive material at the other end of the through-hole is formed; and the high frequency probe is contacted to the second signal testing electrode of the semiconductor device through openings provided, respectively, in the base plate and the elastic sheet.
Further, each of the first and second supply voltage applying electrodes of the contact sheet may have a bump electrode structure. Or else, each of the first and second electrodes of the semiconductor device may have a bump electrode structure.
Furthermore, the first signal-testing electrode on the contact sheet may have a bump electrode structure. Or else, the signal electrode of the semiconductor device may have a bump electrode structure.
Yet further, a bypass capacitor connecting between the first wiring and the second wiring may be provided.
Moreover, the contact sheet may have a larger area than the semiconductor device to be tested.
Further, the semiconductor device may be tested in a semiconductor wafer state in which a plurality of the semiconductor devices are formed. Or else, a form of the semiconductor device to be tested may be a bare chip diced from a semiconductor wafer.
Furthermore, the semiconductor device testing apparatus may further comprise a scrubbing portion. The scrubbing portion includes a piezoelectric device moving the device stage and a controller to control the piezoelectric device so that the electrodes on the semiconductor device and the electrodes on the contact sheet are relatively vibrated at their contact state to break a thin oxide film which has been unfavorably formed on the surface on said electrodes.